2001: American acquires assets of bankrupt TWA; the deal eventually leaves American saddled with old planes and too many employees. On Sept. 11, two American Airlines jets and two United Airlines jets are hijacked by terrorists and crash.

2003: With the company on the brink of bankruptcy, Gerard J. Arpey replaces Carty as CEO; labor unions approve cost-cutting contracts that let AMR avert bankruptcy.

2008: American fails to reach new contracts with union employees, who continue to work under terms of previous agreements.

2009: American announces "cornerstone" strategy of focusing on five big U.S. markets — Dallas-Fort Worth, Chicago, Miami, New York and Los Angeles — while downplaying others.

2010: AMR reports a loss of $471 million, bringing total losses since 2001 to more than $10 billion.

2011: AMR, American Airlines and other subsidiaries file for bankruptcy protection on Nov. 29, a day after Arpey retires and is replaced by Thomas W. Horton.

Feb. 1, 2012: American tells workers that it plans to cut 13,000 union jobs, mostly in the maintenance division; the number is later reduced sharply.

April 20, 2012: US Airways announces that it has reached labor agreements with all three of American's unions on contracts that would take effect in case the two airlines merge.

July 10, 2012: Horton, who had resisted US Airways' merger overtures, says AMR has made enough turnaround progress to now consider merger options.

Aug. 31, 2012: American announces that it has signed an agreement to exchange confidential financial information with US Airways so that the two can study a potential merger.

Sept. 4, 2012: A federal bankruptcy judge reverses his earlier ruling and lets American cut pay and benefits for pilots, who had rejected the company's last contract offer. The decision is followed by a surge in canceled and delayed flights, which American blames on an illegal work slowdown by pilots.

Oct. 2, 2012: American and the Alllied Pilots Association agree to resume contract talks; all other union groups have accepted cost-cutting contracts.

Feb. 13, 2013: The boards of American and US Airways approve a merger creating the world's biggest airline.